Final answer:
Discharge is the volume of water that flows through a river channel over time, influenced by surface runoff and groundwater seepage. It's affected by various environmental factors and is essential for ecological health, irrigation, and drinking water.
Step-by-step explanation:
Discharge is a main output of a drainage basin, which describes the volume of water that flows through a river channel over time. The sources of river discharge are surface runoff and groundwater seepage. Following a heavy rainstorm, discharge typically increases because of the immediate contribution from surface runoff.
However, under normal conditions, the discharge of a river is usually maintained by groundwater seeping into the river. Several factors including precipitation patterns, vegetation cover, topography, land use, and soil characteristics influence the relative contributions of surface runoff versus groundwater seepage. The drainage basin, which includes all the land area drained by a river and its tributaries, plays a crucial role in the hydrological cycle. Larger drainage basins, like the Mississippi River basin, encompass numerous smaller basins such as the Ohio and Missouri River basins.
Discharge is significant as rivers are crucial for irrigation, drinking water supply, and ecological health. However, global concerns exist such as the discharge of untreated wastewater into water bodies, affecting water quality and potentially leading to international disputes over water resources, as seen with rivers like the Colorado and Nile.